It pack contains 2 stools:- Single meteor:Shoot a meteor from the sky or from your tool gun.- Meteor shower:The zone you aim at will be bombed with meteors.The power of meteors and showers can be changed in stool.

This download looks like an addon. You need to extract the downloaded zip and put the addon folder in your Garry's Mod addons folder. You should end up with a directory structure similar to below: